Effect of Retting on the Microstructural, Chemical, and Thermal Properties of Hemp Fibres: Implications for Bio-Based Building Materials

Increasing awareness of the environmental and health impacts of conventional building materials has accelerated interest in bio-based composites that minimise embodied carbon and toxic emissions. Among these, hemp stands out for its fast growth, low agrochemical demand, and potential to contribute to biogenic carbon storage and lower-carbon material development. This study investigates the microstructural, chemical, and thermal properties of hemp fibres to examine their potential relevance to sustainable and health-centred building applications. Using scanning electron microscopy (SEM), Fourier Transform Infrared (FTIR), Differential Scanning Calorimetry (DSC), and Thermogravimetric Analysis (TGA), we evaluated hemp fibre surface morphology, functional group characteristics, and thermal behaviour. Results are interpreted in relation to potential building applications, particularly moisture-related behaviour, low-toxicity material selection, and thermal reliability. The review and characterisation suggest that hemp fibres have potential ecological and technical advantages for future non-structural building materials and composite development, particularly where renewable sourcing, biodegradability, and thermal stability are prioritised. Their porous morphology, cellulose-rich composition, and thermal response suggest potential relevance to moisture-related behaviour, low-toxicity material selection, and future low-carbon building product development. This research suggests that the fibre-level findings may inform the development of low-carbon and health-conscious building composites, although further composite- and product-level validation is required.